1. Field of the Invention
The present invention relates to a thin-film magnetic head with an inductive element, a head gimbal assembly (HGA) with the thin-film magnetic head, a head arm assembly (HAA) with the HGA, a magnetic disk drive apparatus with the HGA, and a manufacturing method of the thin-film magnetic head.
2. Description of the Related Art
In an inductive write head element of a thin film magnetic head, a lower magnetic pole and an upper magnetic pole are usually formed so that their shapes viewed through from their stacked-surface side are almost equal to each other. That is to say, the lower magnetic pole and the upper magnetic pole are formed so that widths at their top ends facing a magnetic medium (widths in the track-width direction) are equal to each other. Here, “top” means an extremity facing the magnetic medium in the direction perpendicular to the air bearing surface (ABS).
In Japanese Patent Publication No. 06-036234A filed by the present assignee, a magnetic head in which the top end widths of the lower magnetic pole and the upper magnetic pole are equal to each other, a magnetic head in which the top end width of the lower magnetic pole is larger than that of the upper magnetic pole, and a magnetic head in which the top end width of the upper magnetic pole is larger than that of the lower magnetic pole are described. However, in the publication, only the magnetic head in which the top end width of the upper magnetic pole is larger than that of the lower magnetic pole in order to decrease fringing fields generated from the side portion of the upper magnetic pole is claimed.
In the case where the top end widths of the lower magnetic pole and the upper magnetic pole are equal to each other as a conventional magnetic head, when the magnetic head is skewed with respect to a recorded track on the magnetic medium, an edge of the lower magnetic pole, which is adjacent to a write gap layer, is run off toward an adjacent track, and is at a risk of erasing some signals on the adjacent track. The risk becomes much higher due to the narrower track width according to heightened recording density.
This influence to the adjacent track when skewed becomes somewhat smaller by making the top end width of the upper magnetic pole larger than that of the lower magnetic pole, however, not small enough.